COMPARATIVE STUDY BETWEEN OSTEOSYNTHESIS IN CONVENTIONAL AND BIOABSORBABLE IMPLANTS IN ANKLE FRACTURES

Are Absorbable Plates More Resistant to Infection Than Titanium Implants? An Experimental Pre-Clinical Trial in Rabbits

Background: Infection of orthopaedic implants after internal fixation of bone fractures remains a major complication with occasionally devastating consequences. Recent studies have reported that the use of absorbable materials, instead of metallic ones, may lead to a lower incidence of postoperative infection. In this experimental pre-clinical animal study, we compared the infection rate between absorbable implants consisting of copolymers composed from trimethylene carbonate, L-polylactic acid, and D, L-polylactic acid monomers, and titanium implants after the inoculation of a pathogenic microorganism. Material and Methods: We used an experimental implant-related infection model in rabbits. Sixty animals were randomly and equally divided into two groups. In all animals, the right femur was exposed via a lateral approach and a 2.5 mm two-hole titanium plate with screws (Group A), or a two-hole absorbable plate and screws (Group B), were applied in the femoral shaft. Afterwards, the implant surface was inoculated with Pseudomonas Aeruginosa at a concentration of 2 × 108 CFU/mL. The primary outcome was the comparison of the incidence of developed infection between the two groups. The wound condition was monitored on a daily basis and radiographies were obtained at 12 weeks postoperatively. Infection-related laboratory markers (white blood cell count, erythrocyte sedimentation rate, and C-reactive protein values) were assessed at 3, 6, and 16 weeks postoperatively. Histologic analysis and cultures of tissue samples were also performed to evaluate the presence of infection. Results: Clinical and laboratory signs of infection were evident in 11 rabbits in Group A (36.7%), and 4 in Group B (13.3%). The difference between the groups was statistically significant (p = 0.04). Five animals in Group B (16.7%) had clinical and histologic signs of a foreign-body reaction with significantly elevated CRP and ESR values but no simultaneous presence of infection was identified (p = 0.04). Bone remodelling with thickening of the periosteum and surrounding sclerosis was demonstrated radiologically in animals developing infection or foreign-body reactions. Conclusions: Absorbable plates and screws show lower susceptibility to infection compared to titanium ones. However, their application is associated with foreign-body reaction and the potential need for a second surgical intervention.

Characteristics and Effectiveness of Postoperative Rehabilitation Strategies in Ankle Fractures: A Systematic Review

OBJECTIVES

To explore the characteristics and to report on the effectiveness of postoperative rehabilitation strategies for people with an ankle fracture.

DATA SOURCES

PubMed, Cochrane Library, EMBASE, Web of Science, and CINAHL were searched to identify studies published from January 2010 to November 2021.

STUDY SELECTION

Studies that described or evaluated postoperative rehabilitation strategies for surgically repaired ankle fractures were included.

DATA EXTRACTION

Data on postoperative rehabilitation were extracted in accordance with the Template for Intervention Description and Replication guide. Quality was assessed using the National Heart, Lung, and Blood Institute's Study Quality Assessment Tools.

DATA SYNTHESIS

Meta-analysis was planned to look at the effectiveness of postoperative rehabilitation strategies. Forty studies described postoperative rehabilitation strategies without evaluating effectiveness, whereas 15 studies focused on evaluating effectiveness. Because of the large variety in postoperative strategies and outcomes, narrative synthesis was deemed most suitable to answer our aims. Characteristics of postoperative rehabilitation strategies varied widely and were poorly described in a way that could not be replicated. Most of the studies (48%) used a late weight-bearing approach, although definitions and details around weight-bearing were unclear.

CONCLUSIONS

Late weight-bearing has been the most common postoperative approach reported in the past 10 years. The variety of definitions around weight-bearing and the lack of details of rehabilitation regimens limit replication and affect current clinical practice. The authors propose to adopt consistent definitions and terminology around postoperative practices such as weight-bearing to improve evidence for effectiveness and ultimately patient outcomes.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Does the Inion OTPSTM absorbable plating system induce higher foreign-body reaction than titanium implants? An experimental randomized comparative study in rabbits

Hardware removal after complete fracture healing is a laborious and traumatic procedure that bears the risks of refracture, infection, and soft tissue damage. Absorbable materials for fracture fixation have the advantage of eliminating the need for removal; however, they may stimulate a considerable inflammatory response. For that reason, we compared in a prospective randomized experimental animal model study the incidence of foreign-body reactions between Inion OTPS^TM absorbable plate implants, consisting of carbon trimethylene, L-polylactic acid, and D, L-polylactic acid, and conventional titanium plates. Seventy rabbits were equally divided into two groups. Titanium (Group A) or absorbable (Group B) plates and screws were implanted in the femoral shaft of the rabbits. Wound reaction and laboratory tests including white blood cell count (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) values were measured and compared at different time points. Radiographs and histological analysis of tissue samples from all animals were also used to identify potential foreign-body reactions. WBC showed normal values in both groups. In Group A, ESR levels were higher at all time points but CRP values were normalized at 3 weeks postoperatively. In Group B, ESR and CRP levels reached a peak at 3 weeks and were above normal values throughout the whole experiment (p < 0.001). Radiologic examination revealed periosteal thickening and surrounding sclerosis in 23 out of 35 animals of Group B (66%). All Group A animals had normal radiographic findings. Histopathology showed a typical non-specific foreign-body reaction in all animals in Group B (100%) but none in Group A. However, only four of them (11.8%) developed non-infected wound complications and showed significantly elevated CRP and ESR values (p = 0.054). Although Inion OTPS^TM Biodegradable Plating System stimulates a foreign-body reaction, only a small but not negligible percentage of almost 12% may lead to wound problems. However, this difference compared to titanium plates was of borderline not statistically significant. Future studies should focus on the development of absorbable implants with improved biocompatibility aiming to further decrease the potential of foreign-body reaction and eliminate the need for additional reoperative procedures.

Lateral wall osteotomy combined with embedded biodegradable implants for displaced intra-articular calcaneal fractures

Background

The extensile lateral approach (ELA) has been widely used to treat displaced intra-articular calcaneal fractures (DIACFs) and remains the gold standard procedure. Orthopedic surgeons are extremely concerned of the high rate of wound complications. This study intended to report a new surgical technique of the lateral wall osteotomy combined with an embedded biodegradable implant for treating DIACFs and assess clinical and radiological results.

Methods

From May 2013 to December 2015, a total of 17 patients with 19 calcaneal fractures underwent surgical treatment using our new technique. Radiographic images, computed tomography (CT) scans, and magnetic resonance (MR) images of the operative limb were obtained to assess fracture healing and biodegradable implant degradation. American Orthopaedic Foot and Ankle Society (AOFAS) ankle/hindfoot score at the last follow-up was obtained to assess functional result for all cases. Böhler’s and Gissane’s angles, width, and height of the injured calcaneus were analyzed using preoperative and last follow-up radiographic images.

Results

All radiological parameters were significantly improved at the last follow-up, with an increase of 15.58°, 8.38°, and 7.65 mm in Böhler’s angle, Gissane’s angle, and calcaneal height, respectively, and a decrease of 2.51 mm in calcaneal width (p < 0.05). Mean AOFAS score at the last follow-up was 84.37 ± 9.98, with 9, 6, and 4 feet, having excellent, good, and fair rates, respectively. None had nonunion, delayed union, or malunion after a mean follow-up of 34.69 ± 5.22 months. One superficial infection occurred 6 days post-surgery.

Conclusions

Osteotomy of the lateral wall of the calcaneus allows tension-free suturing and avoids damage to penetrating branches of the lateral calcaneal artery (LCA). Biodegradable implants are easy to reshape and do not require surgical removal. However, they should be limited to Sander’s type II and III fractures only.

Level of evidence

Level IV, case series without controls